Electric stove



(No Model.)

C. E. ROEHL.

ELECTRIC STOVE. No. 532,909. Patented Ja,11.22,l895.

ngz.

i lll UNITED STATES PATENT OFFICE.

CHARLES EDVARD ROEHL, OF ST. JOSEPH, MISSQURI.

ELECTRIC STOVE.

SPECIFICATION forming part of Letters Patent No. 532,909, dated J'anuary 22, 1 895.

Application tiled January 4, 1 894. Serial No. 495,698. (No model.)

To @ZZ when?, t may concern:

Be it known that I, GHARLEs EDWARD ROEHL, a citizen of the UnitedStates, residing at St. Joseph, in the county of Buchanan and State ofMissouri, have invented certain new and useful Improvements in ElectricStoves, of which the following is a full, clear, and exact description.

This invention relates to electric stoves or heaters, the primary objectbeing to provide an apparatus which may replace the ordinary cookingstove of a kitchen.

To be more exact, the apparatus which I have invented is electricallyheated and is so constructed that the cooking utensils or other devicesused in a kitchen in connection with the stove may be heated by merelyplacing the said devices upon the heater in the same manner that theywould be manipulated in connection with an ordinary stove.

In another application tiled by me on the 22d of November, 1893, SerialNo. 491,628, I have described and claimed an apparatus much similar tothe one herein referred to, but the present invention is an improvementupon the invention described in the earlier application.

In the accompanying drawings, Figure I represents a side elevation of myimproved electric stove, shown somewhat conventionally and illustratingalso the electric circuits. Fig. 2 is a plan of the same without thecircuits. Fig. 3 is a transverse section of the magnetic core of theelectrical apparatus. Fig. et is a detail showing a modification. Fig. 5shows a cross section of a portion of the secondary conductor.`

My electric stove is operated by alternating, pulsating, intermittent,or other irregular currents, and embodies the principle of a transformerA represents a source of current of the nature specified and a theprimary coil of the transforming apparatus of the stove. The coil issupplied with current from the source A and is divided into a number ofsections and connected with a suitable switching apparatus B, by whichany number of sections may be made active at will. C is the magneticcore of the transforming apparatus. It

is constructed in any of the usual ways, being preferably of laminatediron and having a cross section similar to that shown in Fig. 3. Ininductive relation to this magnetic core is placed a copper bar D oflarge cross section, which is bent or looped into the form shown in theseveral figures. This bar constitutes a secondary coil or circuit of thetransforming apparatus. Its free ends CZ are arranged parallel t0 eachother and with their upper surfaces in the same horizontal plane, toform a kind of table similar to the top of a stove. To one of these freeends d is permanently attached a series of rods d of material of higherelectrical resistance than copper. The connection between these rods andthe bar d may be of any suitable character, but I have shown them bentand extending into holes therein. The rods extend transversely from oneof the bars d above and across the other and the series of rods isdivided up into gangs or sections of four, or any other desired number,and the free ends of each gang are connected to a common metallic blockd2 which is arranged parallel to the copper bar and in substantially thesame plane, but out of contact therewith. Each block is provided with acontact brush or spring d3 and an adjusting screw d4, by means of whichthe spring may be thrown into contact with the bar CZ. In this mannerthe electric circuit is completed across the ends d, d and the entiresecondary is thereby short circuited through the rods d. In thissecondary circuit, therefore, the rods will form the part of highestresistance and the relative resistances of these parts will be designedso that when the proper current is induced in the secondary circuit therods only will be the parts heated, in the manner hereinafter described.

It is obvious that it makes no difference which of the bars d, d therods dare permanently fixed to, and in fact the sections or gangs of therods may be alternately fixed to one and the other of the bars.Furthermore, in Fig. 4 is illustrated a construction in which the rodsof one gang alternate with those of another, the fixed ends of the rodsbeing connected respectively to the bars. In this way, and in variousother ways which are obvious, the heating devices may be concentrated ina small space and the regulation of the heat accomplished by throwinginto circuit any number of the rods.

IOO

W inn the electric currents of the character hereinbefore mentioned areflowing in the primary coil a and the circuit of the secondary is closedacross the bars d, d through one or more of the rods d', a heavy currentof low potential will be induced in the secondary circuit which, beingconi-ined therein, will tend to heat it and the portions of this circuitof greatest resistance will be heated to the highest degree. Theseportions, being the rods d', will, if properly constructed, be rapidlyheated to a very high heat and any device such as a stew pan, kettle,flat iron, or other kitchen utensil which is placed upon or adjacent tothe rods d will be heated by conduction and radiation therefrom andcooking may be accomplished with the ordinary utensils and the samemanipulated in the old fashioned manner. Figs. l and 2 show kitchenutensils in position upon the stove to be heated. Narrow strips of micamay be placed between the utensil and the rods if desired, to preventthe current from Flowing through the utensil itself and thus modifyingthe resistance.

The bar D constituting the secondary conductor is here shown as bentinto a single convolution and its ends only bridged by the and that thebridge pieces d may be arranged to bridge the adjacent convolutions insubstantially the same manner as they are a1'- ranged to bridge the endsof the single convolution shown in the drawings.

Having thus described my invention, I claim- In an electric stove orheater, the combination of a transformer or other electrical indnctoriumWhose secondary coil is normally open, a series of high resistance rodsin positive electrical connection with one side of a convolution of thesecondary coil, said rods being grouped into sections or gangs, those ofeach section being connected to a common block, d2, of conductingmaterial, and a contact spring and adjusting screw therefor whereby saidblock may be thrown into and out of electrical connection with the otherside of said convolution of the secondary coil.

In testimony whereof I subscribe my signature in presence of twowitnesses.

CHARLES EDWARD ROEIIL. lilitnesses:

Jos. B. SHIRLEY, G. W. CALDER.

